Hot plug



March 4 ,v '1924; 1,485,890

H. F. SHEPHERD HOT PLUG -Filed oct. 1s, 1921 Patented Mar. 4, 1924.

UNITED STATES PATENT OFFICE.

PENNSYLVANIA.

y HAROLD F. SHEPHERD, OF GROVE CITY, PENNSYLVANIA, .ASSIGNOR TO THEBESSE'MER GAS ENGINE COMPANY, 0F GROVE CITY, PENNSYLVANIA, A

CORPORATION HOT PLUG.

Application led October 13, 1921.

To all ywhom it may concern:

Be it known that I, HAROLD F. SHEPHERD, a citizen of the United States,residing at Grove City, in the county of Mercer and State ofPennsylvania, have invented new and useful Improvements in Hot Plugs, ofwhich the following is a specification.

The invention is especially designed for hot plugs for explosive enginesand is particularly desirable where it is electrically heated. Hot plugsof this general type have been previously invented by me as indicated inPatent #1,317,900, Oct. 7th, 1919.

The invention is illustrated in the accompanying drawing which shows avertical central section through the plug.

1 marks a mounting having a shoulder 2 which is adapted to lit into anopening leading to the explosive chamber of an exw plosive engine, themounting being provided with perforations 3 through which the attachingbolts extend. A projection 4 extends from the mounting 1, and thereceptacle 5, .the walls of which form the hot plate, is on the end ofthe projection 4. This receptacle is preferably cylindrical and closedby a cap 6 having its joint sealed by welding 7. An electrical element 8is preferably arranged in the receptacle 5 and one end of the conductor9 of said element is grounded in the receptacle. The conductor with theusual element sheath is led out through an opening 10 in the projection4, the passage 10 extending through the mounting. The conductor isinsulated by the sheath from the walls of the opening 10 and extendsthrough the insulating cap 11 and is connected to a terminal 13, theterminal being secured to the usual wire in the usual manner.

The receptacle is filled with mercury, or some similar substance,vaporizing at a temperature which is the desired ignition temperature ofthe wall forming the hot plate on the receptacle. The end of theconductor 9 contacts with its sheath as shown at the right of the figureand this sheath being immersed in the mercury grounds this end of theconductor through the mercury and the walls of the receptacle. A passage16 is formed in the projection but off-set from the passage 10, theouter end of this passage being closed by a plug 17. An upwardly eX-tending projection 18 is formed on the mounting 1 and has a passage 19leading Serial No. 507,519.

from the passage 16 and forming a connection with a condensing chamber'20, the walls 21 of which are provided with a corrugated surface so asto increase the condensing surface. A screw-threaded end Q2 is arrangedat the bottom of the condensing chamber and this is screwed into vthetop of the projection 18 and the joint welded by welding at 23.

W'ith this construction the hot plug may extend horizontally in thecombustion chamber and the condensing chamber may be arranged verticallywithout the combustion chamber, thus making a very desirable andconvenient arrangement. In starting the engine, the current is turnedinto the heating element, the mercury heated to an ig nition temperatureand the heat thus conveyed to the walls of the receptacle. After theengine is started and the hot plug is subjected to the explosiontemperature the hot plate is maintained at this desired temperature bythe constant vaporization of the mercury which carries the heat into thecondensing chamber where it is dissipated through the walls of thecondenser and the mercury as it is condensed is returned to thereceptacle 15. In this way a constanttemperature is maintained in thereceptacle in the manner expressed in my former pat-ent. After theengine starts the current is cut off.

What I claim as new is l v 1. In a hot plug, the combination of areceptacle, the walls of which form the hot plate of the plug; amounting from which the receptacle projects; a condenser carried by themounting, said condenser being out of alinement with the receptacle andarranged above the same; a connection between the condenser and thereceptacle; and a liquid in the receptacle vaporizing at the desiredpredetermined temperature.

2. In a hot plug, the combination or" a receptacle, the walls of whichform the hot plate of the plug; a mounting from which the receptaclerejects horizontally; a con denser carried y the mounting and extendingvertically therefrom; a connection between the condenser and thereceptacle; and a liquid in the receptacle vaporizing at the desiredpredetermined temperature.

3. In a hot plug, the combination of a receptacle, the walls of whichform the hot plate of the plug; a mounting from which the receptacleprojects; a condenser carried hv the mounting, Suhl Condenser heine' utof t e. heating element arranged ln the receptacle,

In a hot plug. the Curubmutwu et u rel 4- HCL eeptacle` the Wullg 0lEuluch form the plate of the plug: u meutuiugj trou, Wl

the receptacle gru/eels: a :er eu" by the mfrvuutuzlg. SP1 Ceurlemerlieu;

Ll of mueu'leut with the l receptacle um, ui'- runmul uhove the Su hereeeptuel meule tu t 1e ref Yuporzuv' e (l Cretl ggrefleteruuum upruture: u heu'tlujj element urruu 'he recepuele: uml Coniluf'tor lef( ut (mu 'mt plate of the plug: u mouutius from uhh-h the reeeatacle )roects: hmlxuutullv: u Coudenser Carried by the mounting and extendingYertically there'rom; a connection between the Condenser und thereceptacle; :1 liquid u the receptacle Yuporizug at the le sretlpredeternuuefl temperature; u heating elexueut iu the receptacle; und uconductor leading through the umuutug, Suhl Coutluc tor being off-setfrom the connection betu'eeu the cuufleuger und the receptacle.

(S. In au electrically heated hot plug. thel l'iuutlou of u reeepuele.fue wall@ of my hand.

HAROLD F. SHEPHERD.

